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JSP application scope objects in Java library

Answer 1

+1 A:

Application scoped objects are stored as attributes of the ServletContext. If the "function call" has access to the ServletContext, then it can just grab them as follows:

Bean bean = (Bean) servletContext.getAttribute("beanname");

I of course expect that the "function" is running in the servlet context. I.e. it is (in)directly executed by a servlet the usual way.

BalusC 2010-06-02 12:23:34

Actually, I don't think it is. The appropriate classes are imported in the JSP (via `<%page import%>` directives), and called. How can they run in a servlet context?

FrontierPsycho 2010-06-02 12:28:10

Ouch, poor practice. Anyway, the servlet context is available in JSP *scriptlet* as well by the implicit `application` reference. E.g. `<% Bean bean = (Bean) application.getAttribute("beanname"); %>` and so on.

BalusC 2010-06-02 12:35:31

So what you're saying is that I have to pass the Bean to the function, unless I redesign the application. :) In brief, how would I correct the design?

FrontierPsycho 2010-06-02 12:38:43

Either pass bean or `ServletContext` to function, yes. As to correcting the design, don't do that on existing webapps. It's a waste of time. As to how to design properly, check the "front controller pattern" and "MVC pattern". This site brings you step by step in a correct manner to a good MVC approach: http://courses.coreservlets.com/Course-Materials/csajsp2.html

BalusC 2010-06-02 12:45:31

I am familiar with MVC design, I just don't know how to implement it in JSP. Unfortunately this app was given to me as is. Thank you for the help!

FrontierPsycho 2010-06-02 12:54:05

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JSP application scope objects in Java library

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